Laminate flooring usually comprise of a core of 6-11 mm fibreboard, a 0.1-0.8 mm thick upper decorative surface layer of laminate and a 0.1-0.6 mm thick lower balancing layer of laminate, plastic, paper or like material. The surface layer provides appearance and durability to the floorboards. The core provides stability, and the balancing layer keeps the board plane after pressing and when the relative humidity (RH) varies during the year. The floorboards are laid floating, i.e. without gluing, on an existing subfloor. Traditional hard floorboards of this type were usually joined by means of glued tongue-and-groove joints. However the majority of all laminate floorboards are presently joined mechanically by means of so-called mechanical locking systems. These systems comprise locking means, which lock the boards horizontally and vertically. The mechanical locking systems are usually formed by machining of the core. Alternatively, parts of the locking system may be formed of separate materials, for example aluminium or plastic, which are factory integrated with the floorboard.
The main advantages of floating floors with mechanical locking systems are that they can easily and quickly be laid by various combinations of angling and snapping. They may also easily be taken up again and used once more at a different location.
The most common core material is a fibreboard with high density and good stability usually called HDF—High Density Fibreboard. Sometimes also MDF—Medium Density Fibreboard—is used as core.
A laminate board which comprises a surface of melamine impregnated decorative paper, plastic, wood, veneer, cork and the like are made by the surface layer and preferably a balancing layer being applied to a core material that in addition to HDF may be made of plywood, chipboard, plastic, and various composite materials. Recently a new board have been developed where a powder, comprising fibres, binders, wear resistant particles and colour pigment, is scattered on a core material and cured by heat and pressure to a solid paper free surface.
As a rule, the above methods result in a laminate board, which is divided by sawing into several panels, which are then machined to provide them with a mechanical locking system at the edges. A laminate board of the size of a panel, which is not necessary to divide, may be produced by the above method. Manufacture of individual floor panels usually takes place when the panels have a surface layer of wood or veneer.
Floorboard with mechanical locking systems may also be produced from solid materials such as solid wood.
In all cases, the above-mentioned floor panels are individually machined along their edges to floorboards. The machining of the edges is carried out in advanced milling machines where the floor panel is exactly positioned between one or more chains and belts, so that the floor panel may be moved at high speed and with great accuracy past a number of milling motors, which are provided with rotating diamond cutting tools or metal cutting tools and which machine the edge of the floor panel. By using several milling motors operating at different angles, advanced joint geometries may be formed at speeds exceeding 200 m/min and with an accuracy of about ±0.05 mm. The accuracy in the vertical direction is generally better than in the horizontal direction since it is difficult to avoid so called swimming which occurs when panels move horizontally in relation to the chain/belt during milling.